Being Asian and American is often a complex balancing act.

The challenge for millions of people is managing to assimilate into American society while maintaining the principles of cultural heritage.

About 13.5 million U.S. residents say they are Asian or a combination of another race and Asian, according to a 2004 census report. The number represents 4.7 percent of American households.

The 1990 census counted 6.9 million Asians.

The demographic includes dozens of ethnic groups, languages, religions, customs and origins from across the globe, stretching from Japan and China to Pakistan and India. Academic observers and community members say the diversity within the group is so rich and disparate, it seems folly to treat it as a single bloc.

For example, the experiences of South Asians, who come from the Indian subcontinent and surrounding areas, are distinct from those of East Asians, especially in the post-9/11 world, where fears of racial profiling and discrimination are widespread.

There are also vast differences between the experiences of Asian-Americans born in the United States and those who have newly immigrated.

Despite the lack of definition, there are some experiences common to the disparate groups.

A January 2007 study led by Derald Wing Sue, a professor of psychology and education at Columbia University in New York City, found several common themes among Asians-Americans regarding race and stereotypes.

Many Asian-Americans, for example, feel they are not completely accepted as Americans despite roots that go back several generations, the study found.

The perception is the result of everyday slights and indignities, which are, in many cases, unintentional.

"I was born here and I speak only English, and yet many expect me to know an Asian language," Conan Hom of Lexington, Massachusetts, wrote in an I-Report to CNN.com.

"In fact, I'm often asked, Where am I from? Or what am I? And when I answer U.S. (or American), I'm told, 'No, really, tell me.' "

Many Asian-Americans also feel their complaints of discrimination are left out of racial dialogues, which primarily focus on white and black relations or white and Latino relations, according to the Columbia study.

Praise that excludes, debilitates

While their parents and grandparents faced racism, the types of discrimination aimed at Asians today is more subtle and invisible to the general public, Sue said.

"When I get out of a cab after having a conversation with a white cab driver, they'll say something like, 'Boy, you speak excellent English,'" he said.

"From their perspective, that's meant as a compliment, but another hidden meaning is being communicated, and that is that I am a perpetual foreigner in my own land."

The "model minority" stereotype -- a phrase often used to describe the economic and academic success of the Asian-American community relative to other minorities -- is a debilitating factor, even it is sometimes viewed as praise, Sue said.

It perpetuates the cultural taboos about reporting mental illness or emotional problems, he said. It also glosses over economic and educational inequities among the many Asian groups.

The stereotype also has the power to pigeonhole Asian-Americans, perpetuating the idea that Asian-Americans can succeed only in areas such as math and science.

Calvin Sun, a 20-year-old junior at Columbia, is studying biochemistry but has a passion for filmmaking and works at MTV in his spare time. The cultural stereotype cuts both ways, he said, especially for the generation currently making its way through high school and college.

"Our parents still push to be successful in a way that they feel will be successful, like math or science," he said during a telephone interview. "There is a huge question between what makes you happy and what makes you successful."

"Why can't I do both?" he said, and later answered his question, mischievously raising the possibility of making a movie about scientists.

Moving 'beyond Apu'

Yet, the environment has changed considerably for Asian-Americans during the last 20 years.

Though critics say they are still vastly under-represented, there are more Asian-Americans visible across society's many roles -- from media and popular culture to sports and the business world.

"You can't say we've gone beyond the model minority myth," said Nitasha Sharma, a professor of Asian-American studies and African-American studies at Northwestern University. "But I definitely think it's moved beyond Apu," the Indian convenience store clerk on "The Simpsons."

Technological advances like e-mail, the ease of international travel and reverse migration -- thanks to the global economy -- are reducing some of the angst related to keeping customs intact.

Meanwhile, the proliferation of ethnic communities and cultural organizations is providing a better context for fitting in, Sharma said.

"I think issues of assimilation and integration -- am I Asian? Am I American -- will be always be there. But I think we understand that," she said.

Sharma said she was curious about how the Asian-American community would deal with emerging issues like homosexuality and interracial relationships.

Other looming generational issues like the impending retirement of the baby boomers will spotlight the differences between the Asian custom of caring for the elderly at home versus common Western practices, Sharma said.

"There is now the opportunity to say, 'What are we going to do with our success?' " she said.